Menu
Asus V8440 TD and V8460 ultra TD in the test: Two 'Ti' tans among themselves

Asus V8440 TD and V8460 ultra TD in the test: Two 'Ti' tans among themselves

Anisotropic filtering

The aforementioned disadvantages (or better: nonexistent advantages) inherent in multisampling in the treatment of textures during the FSAA mean that the image quality of multisampling cannot be compared with that of classic supersampling appear. Since the GeForce3, howevernVidia's DirectX-8 chips have the ability to perform true anisotropic filtering. The GeForce2 core and with it the GeForce4 MX series were also able to do this to a limited extent.

What does it mean to filter anisotropically? It literally means to filter in different directions of the measurement with different properties. Usually, for each bilinearly filtered pixel, the immediately adjacent pixels are used to average the color value. With a trilinear filter, color values ​​from the various MipMap levels are also used at the MipMap transitions.

In contrast to the two methods described, anisotropic filtering now uses not only the pixels in the immediate vicinity to form a color mean value, but mostly going into the 'deep' of the image, additional color values ​​and thus largely avoids the well-known blurring with distant textures and annoying pixel flickering, which is not prevented by multisampling alone (in contrast to supersampling).

From left to right: Bilinear, Trilinear, 2xAF, 4xAF and 8xAF

Especially good to recognizable is the effect of anisotropic filter on the floor tiles in the rear region.

There are different approaches to anisotropic filtering to realize. nVidia uses the computationally more complex method, which is a real anisotropicFiltering in conjunction with a trilinear filter enabled. ATi, on the other hand, relies on an adaptive algorithm that only filters anisotropically in those parts of the image where it really has advantages in terms of image quality. Obviously, it has an extremely positive effect on overall performance in conjunction with anisotropic filtering. Unfortunately, this only happens in connection with a bilinear filter, so that the picture quality can suffer under certain circumstances.

A small note should be made here: In the drivers of both nVidia itself and Asus there is none Possibility to set the level of the AF under Direct3D. You either have to do this yourself or use one of the usual tweakers (Rivatuner, nVMax or GTU).

3DMark 2001 SE + AF

First, as usual, the standard Benchmark this and last year, the 3DMark2001 SE.

3DMark2001 SE + AF
Unit: points
  • 1024x768x32Bit:
    • Asus V8460 ultra
      9.541
    • Asus V8440
      9.090
    • GF4 Ti4200 (250/222MHz)
      8.667
    • GF4 Ti4200 (225/250MHz)
      8,548
    • Asus V8460 ultra '2xAF' ​​
      7,840
    • Asus V8440 '2xAF' ​​
      7.394
    • GF4 Ti4200 (250/222MHz) '2xAF' ​​
      6.904
    • Asus V8460 ultra '4xAF'
      6. 901
    • GF4 Ti4200 (225/250MHz) '2xAF' ​​
      6.630
    • Asus V8440 '4xAF'
      6,432
    • Asus V8460 ultra '8xAF'
      6.262
    • GF4 Ti4200 (250/222MHz)'4xAF'
      5,843
    • Asus V8440 '8xAF'
      5.771
    • GF4 Ti4200 (225/250MHz) '4xAF'
      5.604
    • GF4 Ti4200 (250/222MHz) '8xAF'
      5.202
    • GF4 Ti4200 (225/250MHz) '8xAF'
      4,918

If you consider the low losses suffered by the ATis Radeon8500 when using an anisotropic filter , the GeForce4 does not do particularly well here. One of the reasons is that the 'real' anisotropic filtering, as performed by the GeForce, the other is evident from the following graphic.

3DMark 2001 fill rate
Unit: points
  • Without AF:
    • Asus V8460 ultra 'Multitext.'
      2.309
    • GeForce3 'Multitext.'
      1.372
    • Asus V8460 ultra 'Singletext.'
      1,053
    • GeForce3 'Singletext.'
      662
  • With AF:
    • GeForce3 'Multitext.'
      807
    • Asus V8460 ultra 'Multitext.'
      611
    • Asus V8460 ultra 'Singletext.'
      611
    • GeForce3 'Singletext.'
      412

Obviously the GeForce4 chip for some reason does not use its second TMU (Texture Mapping Unit) while performing anisotropic filtering at the same time. This is not a malfunction of our test sample and occurs with the official drivers used and also the new, unofficial Detonator 28.90.

On thenext page: Quake III Arena + AF

Comments